v1.2.1 — custom icons + 3 new rich panels + tools audit

Follow-up polish for v1.2.0's new-module batch.

Icons: the 12 modules added in v1.2.0 were falling back to the sidebar's generic
glyph — they had an emoji in the registry but no entry in the hand-drawn icon set.
Added a proper line icon + tint color for each, matching the rest of the modules.

Audit: read all 34 new tools end to end. Every one mutates the real Live Set or
processes the clip's real audio — nothing demo or stubbed.

3 new rich panels for the modules where the autoform genuinely fell short:

• Strip Silence — visual RMS silence map before trim/split
• Transient Tools — real onset markers on a timeline, live sensitivity slider
• Linked Clips — group manager (list/sync/unlink), replacing hand-typed refs

144 modules · 414 tools · 119 rich panels · 90 quick actions · 325/325 tests.