feat(0098): CLI clap migration (iteration 1) — scoped help, --version, GNU flags

Replace the hand-rolled aura-cli argv parser with a clap derive parser.
Delivers, all from one declarative source:
- scoped `aura <sub> --help` (stdout, exit 0) — each subcommand's own Options
  section; retires the #131 uniform-global-blob help
- `--version` / `-V` → `aura 0.1.0` (stdout, exit 0)
- GNU `--flag=value`, the `--` end-of-options terminator, and long-option
  abbreviation (`--harn` → `--harness`)

Architecture: one root Cli/Command enum, one `*Cmd` struct per subcommand. The
four dual-grammar subcommands (run/sweep/walkforward/mc) map the loaded-blueprint
branch as an optional `[blueprint]` positional + a post-parse `is_file()`
dispatch on a single-sourced predicate; each built-in handler re-asserts a
stray-positional guard (refuse-don't-guess) so clap's optional positional cannot
silently swallow a typo (pinned by two new E2E tests). The execution layer
(run_*/emit_*/runs_*/reproduce_*) is untouched — only arg-plumbing changes, via
thin `*_from` adapters reusing the existing value helpers.

Exit codes behaviour-preserved: clap parse errors exit 2 (matching the old
usage-error=2); domain refusals stay exit 2; reproduce-diverged stays exit 1.
The exit-code split (2=usage / 1=runtime) is iteration 2. clap is admitted under
the C16 per-case review (research-side CLI, invariant 8 untouched — a dev-loop
compile tax, not a frozen-artifact tax).

Forced plan corrections (implementer; verified against the diff):
- Step 6's deletion of the `parse_*_args` fns orphaned ~34 grammar unit tests
  that called them; those were deleted and that grammar coverage moved to the
  renegotiated cli_run.rs E2E pins (`parse_select` kept + retested).
- run_malformed_cost_value_...: a bad cost value is now a clap value-parse error
  (no "Usage:" line); renegotiated to pin exit 2 + empty stdout + the flag name
  "--cost-per-trade"; the units note stays pinned via `run --help`.
- `allow_hyphen_values` on the three cost flags so `--cost-per-trade -0.5`
  reaches the non-negativity guard (else clap rejects -0.5 as an unknown option).
- Deleted the now-dead `RealWindowGrammar` (clippy -D warnings).

Orchestrator additions after the loop:
- Enabled long-option abbreviation (`infer_long_args` on the root — one
  attribute, it propagates to subcommands) + a test, closing spec acceptance
  criterion 4 which the plan's RED tests did not cover. Decided to deliver
  rather than amend the spec: the two ratified decisions conflict on this
  low-tier item — Fork B (GNU compliance, getopt_long abbreviates) vs F5
  (LLM/automation-first, human-only niceties deprioritized) — and the cost
  tiebreaker (one attribute, not per-struct work) resolves to deliver.

Carry-on debt (not this iteration): the error-message "Usage:"/"usage:"/bare
casing is now mixed (clap's capitalized "Usage:" beside preserved lowercase aura
messages); a deliberate quality-hold since the casings are pinned by
renegotiated/preserved tests. Cosmetic; a candidate for the iteration-2
exit-code-split cleanup.

Verified green (orchestrator, this session): cargo build --workspace, cargo
clippy --workspace --all-targets -- -D warnings, and cargo test --workspace all
clean (0 failed across every test binary, including the renegotiated cli_run
pins and the new --version / scoped-help / GNU-flag / dual-grammar tests).

refs #175

Cargo.lock

@@ -37,6 +37,56 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "anstream"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "824a212faf96e9acacdbd09febd34438f8f711fb84e09a8916013cd7815ca28d"
+dependencies = [
+ "anstyle",
+ "anstyle-parse",
+ "anstyle-query",
+ "anstyle-wincon",
+ "colorchoice",
+ "is_terminal_polyfill",
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle"
+version = "1.0.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "940b3a0ca603d1eade50a4846a2afffd5ef57a9feac2c0e2ec2e14f9ead76000"
+
+[[package]]
+name = "anstyle-parse"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "52ce7f38b242319f7cabaa6813055467063ecdc9d355bbb4ce0c68908cd8130e"
+dependencies = [
+ "utf8parse",
+]
+
+[[package]]
+name = "anstyle-query"
+version = "1.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40c48f72fd53cd289104fc64099abca73db4166ad86ea0b4341abe65af83dadc"
+dependencies = [
+ "windows-sys",
+]
+
+[[package]]
+name = "anstyle-wincon"
+version = "3.0.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "291e6a250ff86cd4a820112fb8898808a366d8f9f58ce16d1f538353ad55747d"
+dependencies = [
+ "anstyle",
+ "once_cell_polyfill",
+ "windows-sys",
+]
+
 [[package]]
 name = "arbitrary"
 version = "1.4.2"
@@ -65,6 +115,7 @@ dependencies = [
  "aura-ingest",
  "aura-registry",
  "aura-std",
+ "clap",
  "data-server",
  "libc",
  "serde",
@@ -231,6 +282,52 @@ dependencies = [
  "inout",
 ]
 
+[[package]]
+name = "clap"
+version = "4.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1ddb117e43bbf7dacf0a4190fef4d345b9bad68dfc649cb349e7d17d28428e51"
+dependencies = [
+ "clap_builder",
+ "clap_derive",
+]
+
+[[package]]
+name = "clap_builder"
+version = "4.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "714a53001bf66416adb0e2ef5ac857140e7dc3a0c48fb28b2f10762fc4b5069f"
+dependencies = [
+ "anstream",
+ "anstyle",
+ "clap_lex",
+ "strsim",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2ce8604710f6733aa641a2b3731eaa1e8b3d9973d5e3565da11800813f997a9"
+dependencies = [
+ "heck",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
+
+[[package]]
+name = "colorchoice"
+version = "1.0.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d07550c9036bf2ae0c684c4297d503f838287c83c53686d05370d0e139ae570"
+
 [[package]]
 name = "constant_time_eq"
 version = "0.3.1"
@@ -427,6 +524,12 @@ version = "0.17.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed5909b6e89a2db4456e54cd5f673791d7eca6732202bbf2a9cc504fe2f9b84a"
 
+[[package]]
+name = "heck"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
+
 [[package]]
 name = "hmac"
 version = "0.12.1"
@@ -479,6 +582,12 @@ dependencies = [
  "generic-array",
 ]
 
+[[package]]
+name = "is_terminal_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a6cb138bb79a146c1bd460005623e142ef0181e3d0219cb493e02f7d08a35695"
+
 [[package]]
 name = "itoa"
 version = "1.0.18"
@@ -577,6 +686,12 @@ version = "1.21.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9f7c3e4beb33f85d45ae3e3a1792185706c8e16d043238c593331cc7cd313b50"
 
+[[package]]
+name = "once_cell_polyfill"
+version = "1.70.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "384b8ab6d37215f3c5301a95a4accb5d64aa607f1fcb26a11b5303878451b4fe"
+
 [[package]]
 name = "pbkdf2"
 version = "0.12.2"
@@ -771,6 +886,12 @@ version = "0.4.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0c790de23124f9ab44544d7ac05d60440adc586479ce501c1d6d7da3cd8c9cf5"
 
+[[package]]
+name = "strsim"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -839,6 +960,12 @@ version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
 
+[[package]]
+name = "utf8parse"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
+
 [[package]]
 name = "version_check"
 version = "0.9.5"
@@ -958,6 +1085,15 @@ dependencies = [
  "windows-link",
 ]
 
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]
+
 [[package]]
 name = "wit-bindgen"
 version = "0.57.1"