docs(v1): make stable @v1 the default for all new consumers

[aetherxeg-source]

Scope and user intent

ExecSurface v1.0.0 is already published and qualified within its documented Linux x86_64/native-ptrace boundary. New customers should install and integrate this stable release, not Alpha.5/Alpha.6. The historical Alpha.5 recipe contributed in #128 remains immutable, properly scoped and credited; no stale test receipt has been re-labeled as a v1 test.

Changes

• New copy-ready stable-v1 Rust GitHub Actions consumer examples/github-action-consumer-v1.yml, using AETHERXGLOBAL/execsurface@v1, independent native target-success gate, fail-on-review, read-only permissions, checkout credentials disabled, default no-public-evidence-upload, and mandatory externally trusted baseline/policy digest pins.
• New first-party hosted Actions smoke workflow tests the actual public @v1 binary/Action across PASS, REVIEW, BLOCK, ERROR, pins policy and baseline, and checks baseline immutability. Must actually run before qualification, not just be named.
• examples/README.md prominently directs users to v1 and makes the Alpha.5 Python/pytest contribution explicitly historical. Original independent contributor @astrogilda retains credit and frozen evidence.
• Correct stale pre-v1/Alpha-current wording in active docs and link the current recipe from README, GitHub Action guide and docs index.
• Acknowledge the original copy-ready consumer example proposed by @PandaHUN777 in docs: add GitHub Action consumer example #127. Do not misrepresent its unmerged Alpha channel as accepted stable-v1 code.

Gates (open until verified)

• Validate exact-PR-head workflow syntax and hosted run
• Explicit public v1 Action PASS / REVIEW / BLOCK / ERROR and correct target-verdict semantics
• All required CI / security gates green
• No release/tag/profile/policy mutation; no retrospective upgrade of Alpha evidence

This PR changes only onboarding docs, user examples and self-contained qualification tests; stable binaries, release tags and security claims are unchanged.