workflow: drop kind:/state: prefixes from Gitea labels

Labels renamed in Gitea (Tea propagated the rename to all 24
issues automatically):

- kind:milestone   → milestone
- kind:feature     → feature
- kind:todo        → todo
- kind:idea        → idea
- state:in-progress → in-progress

Five live labels total; no semantic ambiguity since milestone,
feature, todo, idea are all "class" and in-progress is the only
"state" — the prefixes were carrying zero distinguishing weight.

In-tree changes:

- CLAUDE.md: Gitea-issues bullet uses the bare label names.
- skills/boss/SKILL.md: Step 1 filter snippets + direction-
  freedom new-milestone trigger drop the prefixes.
- skills/brainstorm/SKILL.md: Step 7.5 tea-issues-create
  template drops the prefix on the --labels argument.

Verification: cargo test --workspace 647/0/2, architect_sweeps
exit 0, zero residual `kind:*` / `state:*` refs outside
docs/specs/ and docs/plans/.

CLAUDE.md

@@ -226,16 +226,16 @@ 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: `kind:{milestone,
-  feature,todo,idea}` (semantic class) and `state:in-progress`
+  issues ls --repo Brummel/AILang`. Labels: `milestone`,
+  `feature`, `todo`, `idea` (semantic class) and `in-progress`
   (work has started). Big chunks that get their own
   `docs/specs/` entry live as Gitea **milestones** (containers);
   smaller items are standalone issues. No formal priority axis —
   "what's next" is an orchestrator judgement call per session,
-  not a pre-set label. `kind:idea` is the "may be cut" marker.
-  The orchestrator owns the backlog: opening new issues,
-  retagging, closing on completion (typically via the
-  `closes #N` commit-body trailer).
+  not a pre-set label. `idea` is the "may be cut" marker. The
+  orchestrator owns the backlog: opening new issues, retagging,
+  closing on completion (typically via the `closes #N` commit-
+  body trailer).
 
 - **`docs/specs/<milestone>.md`** (since 2026-05-09): per-milestone
   design spec produced by `skills/brainstorm`. Hard-gate before any