fix(photon): disable iMessage data detection on styled sends

[fluxkapacitor]

Summary

Markdown messages containing raw URLs 500 in the Photon iMessage provider. The styled send path (plain string + UTF-16 formatting ranges) never sets enableDataDetection on sendText, so the server defaults data detection ON for styled sends — and a raw URL in the text trips it. The previous workaround (send-format.mjs chooseSendFormat) routed URL-bearing markdown to plain text, silently dropping all formatting.

This PR fixes the class at the provider layer: the sidecar's existing pinned-SDK patch mechanism (patch-spectrum-mixed-attachments.mjs precedent) now rewrites @spectrum-ts/imessage's two styled outbound call sites to pass enableDataDetection: false explicitly:

1. sendContent's markdown case → sendText(..., { enableDataDetection: false }) (single-content sends — the path /send uses)
2. send$1's group branch → sendMultipart(..., { enableDataDetection: false }) (group/multipart sends — same 500 class on styled parts)

Result: markdown with URLs sends as one styled message, URL embedded and auto-linked by iMessage. The sidecar's /send no longer needs the URL-gate and sends markdown as markdown. The patch joins the existing postinstall chain so fresh installs get both patches.

Why this shape

• The SDK accepts options.enableDataDetection on both sendText and sendMultipart (see @photon-ai/advanced-imessage) — the provider just never passes it. Explicit false overrides the server default; proven live (below).
• The patch is anchor-based with loud failure: if a future spectrum-ts reshapes the provider, the sidecar exits with a clear error rather than silently 500ing sends.
• Patch-on-startup is the established pattern for this SDK's bugs (patch-spectrum-mixed-attachments.mjs); it self-heals existing installs without an npm bump, and spectrum-ts pins exactly because it ships breaking majors.

Prior art (this is not a duplicate)

• fix(photon): URL markdown 500 + zombie-stream watchdog (salvage #53283 #45580) #73615 (merged) — the current blunt workaround this PR replaces: routes markdown-with-URLs to plain text (salvaged from fix(photon): send markdown messages with URLs as text #53283).
• fix(photon): handle inbound richlinks and fall back on outbound enable_data_detection errors #54406 (closed as "already fixed") — @cacheburner-agent's error-fallback; its write-up explicitly names this exact approach ("patching spectrum-ts's dataDetectionOption … via the existing patch-spectrum-mixed-attachments.mjs infrastructure") as an alternative they chose not to take. This PR is that alternative, implemented.
• photon-hq/spectrum-ts consistent hallucination? #156 (merged) — the true root cause fix upstream (drop enableDataDetection). It landed after our pinned spectrum-ts@8.0.0, which still carries the bug. This patch is the pinned-SDK bridge; when Hermes bumps the pin past consistent hallucination? #156, the anchors fail loudly and the patch is retired.

Verification

• Live E2E (real bridge, real iMessage): applied the identical patch to the installed SDK, sent **bold** + https://example.com through the real provider → returned messageId, arrived as one bubble, bold intact, URL tappable. (Baseline: unstyled sends work; the styled+URL path is the documented 500.)
• Tests: new test_url_markdown_patch.py (6 tests: applies to real anchors, idempotent via marker, fails loudly on reshaped SDK, fails loudly when SDK missing, preserves CRLF). Neighbors test_url_send_path.py + test_spectrum_patch.py green — 15/15.
• node --check on both .mjs files; package.json JSON-valid.

Follow-up (not in this diff)

send-format.mjs's chooseSendFormat is now unused by the sidecar (its module tests still pass). Removing the dead workaround is a separate cleanup — keeping this PR minimal.

[fluxkapacitor]

Closing — no longer needed. The styled+URL 500 is avoided on this project via a Photon-side setting ('replies as markdown?'), verified live with pure upstream code; running raw clean. Thanks for the merge of the original workaround in #73615 either way.