skeleton: plugin layout + docs, skill/agent migration deferred to iter 1

Establishes the repository structure for the skills plugin:
- README + INSTALL describing the two-layer split (plugin
  mechanics vs per-project profile)
- docs/design, profile-schema, pipeline, agent-template covering
  the universal discipline constants and the profile slot model
- templates/project-profile.yml as a copy-and-fill starting point
- templates/CLAUDE.md.fragment with the baseline orchestrator
  rules a project can import
- install.sh / uninstall.sh wiring skills/ + agents/ into
  ~/.claude/ via idempotent symlinks
- skills/ and agents/ directories empty except for migration
  READMEs; the actual SKILL bodies and agent files migrate
  from ~/dev/ailang/skills/ in the next iteration.

No skill or agent runs yet — this commit only stands up the
structure and documents the substitution model.

templates/CLAUDE.md.fragment

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+# Universal discipline fragment
+#
+# Copy these sections into your project's CLAUDE.md to import the
+# baseline rules the skills plugin assumes. Edit freely afterwards —
+# this is a starting point, not a binding template.
+
+## Roles
+
+I am the **orchestrator** of this project, not the implementer.
+The agents under the skills plugin are my workers. I direct
+them, review their output, and integrate it. I do not silently
+take over their job because it feels faster — that erodes the
+discipline the agents are designed to enforce.
+
+### What this means in practice
+
+- **Plan, design, decide** — myself. Architectural choices,
+  scope, invariants, commit bodies, and the contents of the
+  design ledger are my work product.
+- **Implement, refactor, write tests, diagnose bugs** — by
+  default, delegated. Implementer for code changes that follow
+  a fixed design, tester for E2E coverage, debugger for
+  diagnostics, architect for read-only drift review.
+- **Trivial mechanical edits** (one-line fixes, doc typos,
+  rename across N files) — fine to do directly. Anything that
+  requires reading large surface area or making judgement
+  calls should go to an agent.
+- **Verify the work** — agent reports describe intent, not
+  outcome. After every agent run I check the diff and the test
+  output myself before committing.
+
+## Commit discipline and main-branch sanctity
+
+Two rules govern who touches git history and how:
+
+- **Only the orchestrator commits.** No skill agent runs
+  `git commit`. Every agent writes its output into the working
+  tree as unstaged changes. I inspect the result, decide commit
+  shape, and commit. Per-task or per-phase commits are not a
+  goal in themselves.
+- **main HEAD is sacrosanct.** Nobody (including me) runs
+  `git reset` or `git revert` on main. main moves forward only
+  via my commits. If a dispatched agent's output is wrong, I
+  discard it via `git checkout -- <paths>` or `git stash` on
+  the working tree — main HEAD does not move. If something
+  wrong does land on main, the remedy is a forward-fix commit,
+  never a rewind.
+
+## Design rationale ≠ implementation effort
+
+When picking between design options, the rationale must come
+from the substance of the choice: semantics, structural fit,
+what the design permits vs forbids, compositional clarity,
+future-proofing. **Implementation effort is not a rationale.**
+"Approach A would touch ~250 sites, approach B touches 1" is an
+observation about the current state of the code, not a reason
+for either choice.
+
+Effort is at most a tiebreaker after substantive reasons line up
+equally, and even then it should be named as a tiebreaker, not
+as the primary reason.
+
+## Bug fixes — TDD, always
+
+Bug fixes are RED-first, autonomous, no orchestrator gate. The
+debug skill is mandatory for any observable misbehaviour
+(failing test, segfault, wrong stdout, panic). See the debug
+SKILL.md and debugger agent for the Iron Law and four-phase
+process.

templates/project-profile.yml

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+# Project profile for the skills plugin.
+#
+# Drop a copy of this file at <project-root>/.claude/dev-cycle-profile.yml
+# and edit. See ~/dev/skills/docs/profile-schema.md for the full schema
+# and per-key documentation.
+
+paths:
+  spec_dir: docs/specs
+  plan_dir: docs/plans
+  # design_ledger: design/INDEX.md       # optional
+  # design_contracts: design/contracts   # optional
+  # design_models: design/models         # optional
+  code_roots: [src]
+  # bench_dir: bench                     # optional
+
+naming:
+  counter_dirs: []
+  policy: flat                            # stable_per_directory_4digit | date_prefix | flat
+  slug_separator: "-"
+
+commands:
+  build: ""                               # REQUIRED — e.g. "cargo build" or "npm run build"
+  test: ""                                # REQUIRED — e.g. "cargo test" or "npm test"
+  # lint: ""                              # optional
+  regression: []                          # list of shell commands run by audit; non-zero exit = regress
+
+vocabulary:
+  cycle: cycle                            # what a top-level work unit is called
+  subcycle: iteration                     # what a sub-unit is called
+  ledger_entry: contract                  # what one design-ledger entry is called
+
+standing_reading:
+  always:
+    - CLAUDE.md
+    - "git log -10 --format=full"
+  by_role:
+    # architect: [design/contracts]
+    # debugger: ["git log -5 --format=full"]
+
+git:
+  main_sacrosanct: true
+  only_orchestrator_commits: true
+  protected_branches: [main]
+  issue_tracker:
+    kind: none                            # gitea | github | linear | none
+    close_marker: "closes #N"
+
+pipeline:
+  brainstorm: { gates: [planner] }
+  planner:    { gates: [implement] }
+  implement:  {}
+  audit:      { mandatory_at: cycle_close }
+  debug:      { trigger: bug, red_first: true }
+  # fieldtest: { boss_only: true, when: surface_touch }
+  # docwriter: { boss_only: true, when: api_stable_across_n_cycles }