feat: vs mode N full passes + --competitors auto-discovery + (/Last30Days) title (#312)

* feat: vs mode runs N full passes; --competitors wraps vs with auto-discovery

Unifies vs-mode and --competitors onto one fanout architecture. A topic
containing "vs" / "versus" now runs N full pipeline.run() calls in parallel
(reverting the one-pass latency optimization that removed per-entity
depth); --competitors becomes a SKILL.md-level shortcut where the hosting
reasoning model (Claude Code, Codex, Hermes, Gemini) discovers N peers via
its own WebSearch, runs Step 0.55 per entity, and invokes the engine with
a vs-topic + --competitors-plan JSON.

Changed:
- vs-mode: N full passes in parallel via fanout (was 1 merged pass).
- --competitors: SKILL.md shortcut for vs-mode-with-discovery. Engine flag
  kept for headless/cron use. LAW 7-style stderr reframed to lead with the
  hosting-model path (use WebSearch + --competitors-plan) instead of
  BRAVE_API_KEY. Footer BRAVE/SERPER nudge suppressed when --plan or
  --competitors-plan present (hosting model already has WebSearch).

Added:
- --competitors-plan JSON flag: per-entity {x_handle, x_related, subreddits,
  github_user, github_repos, context}. Accepts inline JSON or file path.
  subrun_kwargs_for helper is the single source of truth for per-entity
  kwargs — no closure-default fallthrough from main scope.
- Per-entity save files: each entity's sub-run produces its own
  {slug}-raw.md with a single-row Resolved Entities block.
- --polymarket-keywords filter for ambiguous single-token topics.

Fixed:
- test_competitor_subrun_isolation regression suite locks in 3.0.12's
  no-leak invariant (main flags do not inherit into peer sub-runs).
- Updates test_regression.py for the new comparison-mode payload shape.

Bumps plugin.json to 3.0.13. 1,219 tests passing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix: comparison title attribution — (Last 30 Days) → (/Last30Days)

User feedback on 3.0.13 dogfood runs (Kanye vs Drake, Mercer Island,
Figma): the comparison-mode synthesis title should attribute to the
slash command rather than restate the date range.

Three SKILL.md occurrences updated. Pure documentation change. Bumps to
3.0.14.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Matt Van Horn <455140+mvanhorn@users.noreply.github.com>
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

README.md

@@ -116,7 +116,7 @@ When the same story appears on Reddit, X, and YouTube, v3 merges them into one c
 
 ### Auto-discovered competitor comparisons
 
-`/last30days OpenAI --competitors` discovers the top 2 peers via web search (Anthropic, xAI), runs the full pipeline on each in parallel, and returns one 3-way comparison report. Override with `--competitors=N` (range 1..6) or `--competitors-list="A,B,C"`.
+`/last30days OpenAI --competitors` tells the hosting reasoning model to discover the top 2 peers via WebSearch (Anthropic, xAI), run Step 0.55 per entity, and invoke the engine with `"OpenAI vs Anthropic vs xAI"` and a per-entity `--competitors-plan` JSON. The engine fans out 3 full pipelines in parallel, saves a `*-raw.md` file per entity, and merges them into a 3-way comparison. Same mechanics power `/last30days "OpenAI vs Anthropic vs xAI"` directly.
 
 ### GitHub person-mode