Prevent generic Copy probing in terminal grabs

[c-wri]

Why

COSMIC Terminal live qualification exposed a terminal-input safety defect: when a primary-first grab could not use an affine primary selection, ClipReg injected the global CTRL+INSERT probe before the terminal-specific CTRL+SHIFT+C fallback. In a terminal, that generic Insert-family probe can reach the PTY as a CSI sequence instead of acting as Copy, producing visible ...~ residue.

This PR addresses #5 only. The unrelated clipboard-paste / primary-affinity composition problem remains tracked in #6.

What

• Introduce an explicit grab Copy plan derived from the application profile.
• primary-only: never inject Copy.
• primary-first: use affine primary when available; otherwise inject exactly the profile-defined Copy chord, with no generic probe first.
• ordinary copy: retain the generic safe probe and optional profile fallback behavior.
• Update architecture and app-profile authority to describe the same policy.
• Add a lowest-layer runtime regression that fails if primary-first is routed through the generic probe.

For COSMIC Terminal, the only injected Copy fallback is now CTRL+SHIFT+C.

Validation

Automated/local:

• make check PASS on Pop!_OS 24.04, including strict native compile, runtime lifecycle regressions, binary self-test, client/autostart tests, install rebuild planning, and sanitizers.
• Native rebuild/self-test PASS for 0.2.0-beta.1+g96bd9e674a3b.
• GitHub CI / Check PASS on Ubuntu 24.04.

Live COSMIC Terminal:

• normal affine-primary grabs produced no synthetic terminal residue;
• forced fallback with primary_affinity=invalid produced seven grab-profile-copy attempts and zero grab-safe-copy attempts;
• all seven intentionally failed grabs returned bounded ETIMEDOUT because nothing was selected;
• F12 remained unchanged (REGISTER ONE TEST, same metadata/timestamp), proving failed grabs do not overwrite the register;
• rapid consecutive fallback grabs produced no ...5~, ...14~, CSI residue, or SIGINT;
• NRestarts remained 0 -> 0 and post-test list, doctor, and app remained responsive.

Release impact

#5 acceptance is complete. No version bump or prerelease tag is introduced by this corrective PR. The separate #6 blocker still prevents v0.2.0-rc.1 promotion.

Open / deferred

• Clipboard paste must preserve unrelated terminal primary-selection affinity #6 remains a separate runtime review unit.
• Existing bundled-COSMIC-XML DTD and Make circular-target warnings remain tracked separately and are not widened into this fix.