✨ [RUM-16632] add profiling bridge mode support

[bcaudan]

Motivation

Profiling data is always sent directly to the intake via HTTP. In Electron and WebView environments where the native SDK acts as a proxy through the bridge, profiling requests would use dummy session and application IDs, resulting in rejections at the intake.

Changes

• Add BridgeCapability.PROFILES: route profiling through the bridge when the native SDK advertises it, disable profiling silently when a bridge is present without that capability
• Refactor the profiler to be transport-agnostic: introduce an emitPayload callback so the profiler core no longer owns transport decisions
• Add ProfilingPayload as a shared domain type (profile + trace) passed to both the bridge emitter and the FormData emitter
• Session injection for the non-bridge path moves to formDataEmitter, keeping the bridge path session-free (the native SDK handles it)

Test instructions

Unit tests cover bridge mode routing, session injection, and sampling. E2E test covers the bridge path end-to-end using the mock bridge.

Checklist

• Tested locally
• Tested on staging
• Added unit tests for this change.
• Added e2e/integration tests for this change.
• Updated documentation and/or relevant AGENTS.md file

[cit-pr-commenter-54b7da]

Bundles Sizes Evolution

📦 Bundle Name	Base Size	Local Size	𝚫	𝚫%	Status
Rum	171.79 KiB	172.15 KiB	+364 B	+0.21%	✅
Rum Profiler	7.88 KiB	7.74 KiB	-143 B	-1.77%	✅
Rum Recorder	21.21 KiB	21.21 KiB	0 B	0.00%	✅
Logs	54.31 KiB	54.31 KiB	0 B	0.00%	✅
Rum Slim	129.70 KiB	129.70 KiB	0 B	0.00%	✅
Worker	22.96 KiB	22.96 KiB	0 B	0.00%	✅