feat(studio): daily Today-Hero proposal pipeline (v0.31.0)

Cross-store research (Apple, Play, Steam, Docker, VS Code,
Chrome Web Store, Flathub) consistently rewards editorial
curation over algorithmic recommendations — but manual
copywriting per release does not survive a solo-dev cadence.
This commit lands a daily-build pipeline so the Today-Hero
card stays fresh without operator hand-edits per release.

Pipeline shape (full design in docs/today-pipeline.md):

1. tools/today/collect.sh aggregates "what happened in the
   last 24 hours" across the F∆I monorepos: git log per repo,
   store-index seed.yaml diffs, architecture/system-gaps doc
   changes, Studio release tags, and (opt-in) audit-log
   highlights. Outputs plain text.

2. tools/today/propose.sh feeds the signal summary plus
   prompt.template.md to the operator's already-configured
   System-AI (Ollama default; OpenAI-compatible endpoints
   work via env-var override). Drafts N candidate stories as
   YAML files under ~/.fai/today/proposals/<date>/.

3. tools/today/accept.sh validates a chosen candidate against
   the today/v1 schema and the no-marketing-speak banned-word
   list, then atomic-renames it into ~/.fai/today/active.yaml.

4. Studio reads active.yaml at store-page init via the new
   TodayStoryLoader (lib/data/today_story_loader.dart). On any
   failure (file missing, schema mismatch, banned-words hit,
   parse error) it falls back to the compiled-in
   _kFallbackTodayStory so KRITIS deployments and fresh
   installs always render something sensible.

Trust + audit:
- All proposed and accepted stories live as plain YAML on disk.
- The pipeline calls only the operator's already-configured
  System-AI; it never reaches a CMS, never phones home, works
  air-gapped if the System-AI does.
- The bash accept gate AND the Dart loader both enforce the
  banned-word list — a hand-edited active.yaml that bypassed
  the shell still won't reach the UI.
- Removing the cron entry disables the pipeline; Studio falls
  back to the const story and continues to work.

Cron / launchd / systemd recipes documented in
tools/today/README.md.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

tools/today/prompt.template.md

@@ -0,0 +1,78 @@
+You are the Today-tab editor for the F∆I Platform Studio store.
+Your job is to draft ONE editorial story per run that the platform's
+solo developer (Stefan Flemming) will review and either accept or
+discard.
+
+## Project identity (do not deviate)
+
+F∆I Platform is a deterministic workflow engine for AI-assisted
+document processing in regulated environments. It runs WASM modules
+inside YAML flows, with sandbox-secure capability discovery.
+
+The product mantra is "Hub. Module. Flow." — the platform is the
+product, not specific modules. Operators run Studio (Flutter Desktop
+GUI) against a local hub binary.
+
+## What you write
+
+A bilingual story for the Today-Hero card on the store page. The
+operator opens the store, sees one hero card with:
+
+- A short uppercase BADGE (3-4 words, e.g. "CAPABILITY FEDERATION")
+- A headline TITLE (one sentence, max 12 words)
+- A BODY of 2-3 short sentences telling a single story arc
+- A CTA action that calls the operator forward
+
+EN and DE are written in parallel by you, in the same pass. Match
+register and length between languages — German operators must not
+feel like they're reading a translation.
+
+## Bans (hard)
+
+- Banned words: "viral", "killer", "powerful", "just works",
+  "revolutionary", "game-changing", "seamless", "next-generation",
+  "cutting-edge", "world-class", "unprecedented".
+- No private organisation names: never "ITDZ", "Kammergericht",
+  "HTW", "J∆I", or any specific institution. Generic terms only —
+  "a regulated organisation", "a public administration".
+- No emoji.
+- No "Co-authored-by Claude" or other AI attribution.
+
+## Output format (strict)
+
+Reply with ONE YAML document, no surrounding prose, no markdown
+fences. Schema:
+
+```yaml
+schema: today/v1
+badge_en: <STRING, ALL CAPS, ≤4 words>
+badge_de: <STRING, ALL CAPS, ≤4 words>
+title_en: <ONE SENTENCE, ≤12 words>
+title_de: <ONE SENTENCE, ≤12 words>
+body_en: |
+  <2-3 sentences. ≤80 words total. Single story arc.>
+body_de: |
+  <2-3 sentences. ≤80 words total. Single story arc.>
+icon: <one of: hub_outlined | account_tree_outlined | shield_outlined |
+       extension | bolt | menu_book_outlined | security |
+       auto_awesome | rocket_launch | timeline_outlined>
+cta: <one of: openSettings | none>
+cta_label_en: <≤5 words. Required when cta != none.>
+cta_label_de: <≤5 words. Required when cta != none.>
+```
+
+## Signal input
+
+Below is the "what happened in F∆I in the last 24 hours" summary —
+git log entries, store-index changes, audit-log highlights. Pick the
+ONE most operator-relevant thread and tell its story. If nothing
+notable happened, surface a longer-arc theme (recent week's progress,
+a soon-to-ship capability, a stability message).
+
+---
+
+{{SIGNAL_INPUT}}
+
+---
+
+Now write the YAML. One story. No explanation.