workflow: add BLOCKER Gitea label — preempts everything in /boss

New label for "core functionality broken" — the only category
with a hard precedence rule baked into the skill system, not a
judgement call. No issues carry it today; the label and the
skills must know about it so that the first time one is filed,
the orchestrator handles it without a one-off "what now?"
exchange.

In-tree changes:

- CLAUDE.md: Gitea-issues bullet introduces a "precedence order
  matters" note and lists `BLOCKER` first.
- skills/boss/SKILL.md: Step 1 gains a dedicated `BLOCKER`
  precedence paragraph — every queue read starts with
  `tea issues ls --labels BLOCKER --state open`; if hit, it's
  the next dispatch (RED-first via skills/debug), preempting
  whatever else is in flight. The "finish the current agent
  call first, don't strand a working tree mid-edit" caveat is
  written in.
- skills/brainstorm/SKILL.md: Step 7.5 tea-create template
  flags that BLOCKER can stack on top of the kind label.

Universal bug-fix mechanics (RED-first TDD via skills/debug)
are unchanged — BLOCKER is a precedence tag, not a new
workflow. The /boss "Direction freedom" section continues to
gate cross-milestone hops; BLOCKER is an in-milestone preempt
that doesn't bounce back to the user (it has the orchestrator's
implicit authority by definition).

Verification: cargo test --workspace 647/0/2, architect_sweeps
exit 0.

skills/boss/SKILL.md

@@ -77,6 +77,16 @@ 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`.
 
+**`BLOCKER` always takes precedence.** Before any other pick,
+run `tea issues ls --repo Brummel/AILang --labels BLOCKER
+--state open`. If even one open `BLOCKER` exists, that is the
+next dispatch — preempting current iter, audit, fieldtest,
+anything. Hand off to `skills/debug` for RED-first TDD per the
+universal bug-fix rule. A `BLOCKER` mid-session preempts the
+current step; finish the running agent call first (don't
+strand a working-tree mid-edit), then redirect. Only after the
+`BLOCKER` queue is empty does ordinary pickup resume.
+
 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

skills/brainstorm/SKILL.md

@@ -248,7 +248,7 @@ interpretation:
    ```bash
    tea issues create --repo Brummel/AILang \
      --title "<idea title>" \
-     --labels "<feature|bug|idea>" \
+     --labels "<feature|bug|idea>" \   # add BLOCKER prefix if core-functionality-broken
      --description "<one-line description>
 
    **context:** <why this is deferred>