feat(media): report USDC cost in image/video/music results

[KillerQueen-Z]

Problem

blockrun_image, blockrun_video, and blockrun_music return the URL and model but no price. On a bare MCP — without the plugin's announce-cost skill — the user never sees what a generation charged. The cost is already computed and booked to the budget ledger; it just isn't surfaced in the result.

blockrun_speech and blockrun_realface already print a Cost: line, so this closes the gap on the remaining media tools.

Change

Each of the three tools now appends to its result:

• a Cost: $X.XXXX line in the text output
• a cost_usd field in structuredContent

Cost source, per tool:

• video / music — the real 402-settled amount (amountToUsd(details.amount)). Both are token-priced upstream, so 1080p/4K clips and long tracks can exceed the per-unit estimate — showing the settled figure is the accurate one.
• image — catalog estimate on Base (the SDK response carries no billed amount), real 402 amount on Solana.
• All three fall back to the estimate only if the quote doesn't parse.

No new spend path and no change to what is charged — the figure shown is the same amount already recorded to the budget.

Example (video)

🎬 Video ready!
URL: https://blockrun.ai/media/vid_123.mp4
Duration: 8s
Model: xai/grok-imagine-video
Cost: $0.4000        ← new
Backed up to BlockRun storage (URL is permanent)
Request ID: req_789
Tx: 0xabc123txhash

Tests

Adds handler-level tests for the image / video / music footers with the HTTP layer and the x402 payment helpers mocked — no network, no real spend. node --test isolates each file in its own process, so the module mocks don't leak. The test script now runs with --experimental-test-module-mocks.

npm test → 96 passing. npm run typecheck clean.

Not included

chat / chat-anthropic (LLM completions — have a real settled price) and the small-ticket data tools (search, exa, surf, markets, rpc, defi, modal, phone) still omit a cost line. Happy to follow up in a separate PR if wanted — kept this one scoped to the media-generation tools.

[VickyXAI]

Merged via 7321e44. Branch was cut from 0.25.2, so rebasing over the 0.25.3 audit pass needed two conflict resolutions: CHANGELOG (placed 0.26.0 above 0.25.3) and package.json (0.26.0). src/tools/image.ts and music.ts auto-merged cleanly — the cost-footer code sits correctly alongside the 0.25.3 budget-gate hardening. Combined suite green: typecheck clean, 109 tests pass, build OK.

Note: VERSION is now 0.26.0. Heads-up that the 0.25.3 release (e566acd) bumped package.json + CHANGELOG but left VERSION at 0.25.2 — this merge realigned it.