workflow: retire milestone label — Gitea milestone container IS the concept

The `milestone` label was a dead duplicate of Gitea's first-class
milestone container. Zero issues carried it (the three actual
big-chunks — Flat array, Iteration-totality, Stateful islands —
live as Gitea milestone containers, not as labelled issues).
Same pattern as `prio:p1`: a slot that never gets used because
the concept it tries to label lives somewhere else.

Label deleted in Gitea. Remaining labels: `feature`, `idea`,
`in-progress` (three, all semantic, no taxonomy noise). Big-
chunk work continues to live as Gitea milestone containers
(reached via `tea milestones ls --repo Brummel/AILang`).

In-tree changes:

- CLAUDE.md: Gitea-issues bullet describes the three-label
  shape; explicit note that milestone is a Gitea container,
  not a label.
- skills/boss/SKILL.md: Step 1 filter set drops `milestone`,
  adds `tea milestones ls` for the container view; direction-
  freedom "new milestone" trigger reworded around the
  container, not the label.
- skills/brainstorm/SKILL.md: Step 7.5 tea-create template
  drops `milestone` from the choice set; adds a note that
  spec-needing deferred work should be filed as a Gitea
  milestone container via `tea milestones create` instead.

Verification: cargo test --workspace 647/0/2, architect_sweeps
exit 0, zero residual `milestone`-as-label refs in live docs
(grep skip-listed legitimate "Gitea milestone (container)"
prose).

CLAUDE.md

@@ -226,13 +226,14 @@ not retroactively renamed.
 - **Gitea issues** (since 2026-05-20) are the forward queue —
   milestones, features, todos, and ideas. Browse:
   http://192.168.178.103:3000/Brummel/AILang/issues. CLI: `tea
-  issues ls --repo Brummel/AILang`. Labels: `milestone` (needs a
-  `docs/specs/` entry, bounces back to the user in /boss),
-  `feature` (substantive addition, no full spec), `idea` (may be
-  cut, no commitment), `in-progress` (work has started). An
-  unlabelled issue is the default: a concrete task to just do,
-  no spec needed. Big chunks live as Gitea **milestones**
-  (containers); smaller items are standalone issues. No formal
+  issues ls --repo Brummel/AILang`. Labels: `feature`
+  (substantive addition, no full spec), `idea` (may be cut, no
+  commitment), `in-progress` (work has started). An unlabelled
+  issue is the default: a concrete task to just do, no spec
+  needed. Big chunks live as Gitea **milestone containers**
+  (first-class Gitea concept, not a label — needs a
+  `docs/specs/` entry, opening one bounces back to the user in
+  /boss); smaller items are standalone issues. No formal
   priority axis — "what's next" is an orchestrator judgement
   call per session, not a pre-set label. The orchestrator owns
   the backlog: opening new issues, retagging, closing on

skills/boss/SKILL.md

@@ -70,18 +70,20 @@ mode. This skill does not restate them.
 The Gitea issue backlog is the forward queue. Browse:
 http://192.168.178.103:3000/Brummel/AILang/issues. CLI:
 `tea issues ls --repo Brummel/AILang --state open` lists every
-open issue; `--labels milestone` / `feature` / `idea` filters by
-semantic class. Unlabelled issues are the default "just do it"
-bucket. Read a candidate body with
-`tea issues <N> --repo Brummel/AILang`.
+open issue; `--labels feature` / `idea` filters by semantic
+class. Unlabelled issues are the default "just do it" bucket.
+Big chunks live as Gitea **milestone containers** — list via
+`tea milestones ls --repo Brummel/AILang`. Read a candidate
+issue body with `tea issues <N> --repo Brummel/AILang`.
 
 There is no formal priority axis (`prio:*` labels were retired
 2026-05-20). Pick the next item by orchestrator judgement:
 typically the simplest in-flight follow-up to the just-closed
 milestone, then an unlabelled issue or a `feature` that
-unblocks something, then `milestone` (which is itself a
-bounce-back per §"Direction freedom"). `idea` is "may be cut"
-and should rarely be picked autonomously.
+unblocks something, then opening a new Gitea milestone
+container (which is itself a bounce-back per §"Direction
+freedom"). `idea` is "may be cut" and should rarely be picked
+autonomously.
 
 If the entire open backlog is empty: skip to Step 5 (done-state).
 Do not invent work; an empty queue is a real signal that the
@@ -159,12 +161,12 @@ Bounce back to the user only when:
   project's direction (a fundamental design flaw, an external
   dependency failure, a discovered invariant violation).
 - The user has explicitly asked for a checkpoint.
-- **The next item on the queue is a new milestone** — i.e. a
-  backlog issue (typically labelled `milestone`) that has no
-  `docs/specs/` file yet and would require dispatching `brainstorm`
-  to even begin. Continuing an open milestone (next iter, audit,
-  fieldtest, post-audit tidy) is autonomous; *starting* a new one
-  is a bounce-back.
+- **The next item on the queue is a new milestone** — i.e. an
+  open Gitea milestone container that has no `docs/specs/` file
+  yet and would require dispatching `brainstorm` to even begin.
+  Continuing an open milestone (next iter, audit, fieldtest,
+  post-audit tidy) is autonomous; *starting* a new one is a
+  bounce-back.
 
   **Why this is different from the other three triggers.** Cross-
   milestone work is high-context work. A fresh brainstorm alone

skills/brainstorm/SKILL.md

@@ -248,7 +248,7 @@ interpretation:
    ```bash
    tea issues create --repo Brummel/AILang \
      --title "<idea title>" \
-     --labels "<milestone|feature|idea>" \
+     --labels "<feature|idea>" \
      --description "<one-line description>
 
    **context:** <why this is deferred>
@@ -256,7 +256,9 @@ interpretation:
    ```
 
    (Omit `--labels` entirely for an unlabelled default-bucket
-   issue.)
+   issue. If the deferred work is big enough to need its own
+   `docs/specs/` entry on resumption, file it as a Gitea
+   milestone container instead via `tea milestones create`.)
 
 3. Tell the user the spec was retired and which Gitea issue was
    filed (include the issue number). No commit is needed for the