Docs: command/output-format/stability contract docs contradict each other

[codeforester]

Goal

Fix internal contradictions in the command-surface/output-format/stability
contract docs so stability-tiers.md and output-formats.md accurately
describe the actual flag and format contracts documented elsewhere.

Background

A documentation review of the reference/contract layer found:

• docs/stability-tiers.md:81-82 lists --keep-temp among internal flags
  "rejected by basectl" (alongside --debug, --quiet, --config,
  --environment). But docs/command-reference.md:21-25,
  docs/base-cli.md:379-384, and docs/observability.md:169-171 all treat
  basectl --keep-temp <command> as a documented, public wrapper-level flag.
  The same list also omits --log-file, which command-reference.md and
  base-cli.md do list as rejected — this looks like --keep-temp was
  swapped in for --log-file by mistake.
• docs/stability-tiers.md:49-60 ("Stable JSON contracts") omits run --list/build --list, which docs/command-reference.md:100-101
  explicitly calls a "stable, side-effect-free automation contract" — the
  stability registry is incomplete relative to its own source document.
• release check's supported output-format contract is contradictory:
  docs/command-reference.md:178 documents the full
  --format <text|csv|tsv|yaml|json> set, but release check is also one of
  the "shared v1 envelope" inspection commands per
  docs/inspection-json.md:7-11; its siblings (repo check, gh issue readiness, gh branch stale) are documented elsewhere as text|json
  only, and docs/output-formats.md:86-88's exceptions section never
  mentions release check, leaving its actual format contract undefined.
• docs/output-formats.md:90-94's release check CSV/TSV row shape
  (STATUS, NAME, MESSAGE) is never explicitly tied to
  docs/inspection-json.md's nested data.findings[].{status,name,message}
  records, leaving readers to infer how the envelope becomes flat rows.

Scope

• docs/stability-tiers.md
• docs/output-formats.md
• docs/inspection-json.md
• docs/command-reference.md (only if needed to align wording)

Acceptance Criteria

• stability-tiers.md's internal/rejected-flag list matches
  command-reference.md/base-cli.md (fix the --keep-temp/
  --log-file mix-up).
• stability-tiers.md's "Stable JSON contracts" list includes run --list/build --list or explains why it's intentionally excluded.
• release check's actual supported output formats are stated
  unambiguously in one place and match across command-reference.md,
  output-formats.md, and inspection-json.md.
• The CSV/TSV row shape for release check is explicitly connected to
  the JSON envelope fields it's derived from.

Validation

git diff --check; if feasible, run basectl release check --format json
and --format csv against a sample project to confirm the documented
contract matches actual output.

Non-Goals

• Changing actual command behavior — this issue is about correcting the
  documented contract to match (or explicitly reconcile with) reality.

Project Metadata

• Priority: P1
• Size: M
• Area: Docs
• Initiative: Contract Hardening
• Agent Assignment: Human first (requires checking actual CLI behavior
  against docs to resolve the release check format ambiguity correctly)