feat(gitflow): push-mode verb; /close reports the push state instead of pushing

Run C1 of manual-push mode (BDR-111/BDR-112).

- lib/gitflow.sh: `gitflow.sh push-mode` prints auto | manual | invalid
  (rc 0; an invalid value is named on stderr). It is the one reader a
  skill may call: the bare `git config … gitflow.*` read is denied to
  Claude since run B. Ignores GITFLOW_NO_PUSH by design (documented).
- skills/capitalize/SKILL.md STEP 5C: the explicit `git push origin
  develop` is gone — `finish` has pushed develop itself since BDR-095,
  mode-aware since run A. 5C is now three separate read-only calls
  (finish; push-mode; `git rev-list --count origin/develop..develop`)
  and prose outcomes keyed on the real ahead count: pushed / manual push
  mode, you push / not on origin / push FAILED / invalid value named,
  plus a finish-failure outcome (merge vs delete rc distinguished).
  STEP 6 closing lines and the recap carry every outcome; the
  `--no-push` line reads the branch's own ahead count ("this disk only"
  only when true). Invariant: no `git push` inside any Bash call; the
  user hints are prose.
- skills/close/SKILL.md, lib/gitflow-aiguillage.md: "push" claims
  qualified "in auto-push mode".
- lib/gitflow-test.sh T11b: six cases for the verb (default, true,
  false, non-boolean with stderr + rc 0, corrupt config, usage).

Polish items from the gates are listed in TODO.md (C1 polish).

skills/close/SKILL.md

@@ -9,7 +9,7 @@ description: |
   (that is /prune-memory).
   Triggers: "close", "end session", "ferme la session", "session close",
   "checkpoint memory", "what did we learn", "retro rapide", "fin de journée".
-argument-hint: "[--no-push] (runs capitalize in ritual mode; --no-push holds memory on chore/<name>: pushed to origin by the hooks, NOT merged (finish skipped), merge when ready; default = auto-finish into develop)"
+argument-hint: "[--no-push] (runs capitalize in ritual mode; --no-push holds memory on chore/<name>: pushed to origin by the hooks in auto-push mode, NOT merged (finish skipped), merge when ready; default = auto-finish into develop)"
 allowed-tools:
   - Read
   - Edit
@@ -28,7 +28,7 @@ allowed-tools:
 Invoke the `capitalize` skill now and run it in **ritual mode**: the full
 pipeline (STEP 0 precheck → STEP 1 auto-scan → STEP 2 dedup → STEP 2B TODO
 reconcile → STEP 3 approval gate → STEP 4 write → STEP 5 journal → STEP 5B
-memory commit → STEP 5C auto-persist: finish + push, BDR-068 — pass
+memory commit → STEP 5C auto-persist: finish (push rides it in auto-push mode), BDR-068 — pass
 `--no-push` through to hold the chore branch instead → STEP 6 handoff),
 PLUS STEP 1B's explicit 3-question reflection (what did you decide / learn
 / block).