fix(update): platform asset filenames don't include version

[getappz]

Summary

• `agentflare update` 404s on every platform: `asset_name()` built filenames like `agentflare-x86_64-pc-windows-msvc-1.3.0.zip`, but the release workflow only versions the source tarball — platform binaries ship as `agentflare-x86_64-pc-windows-msvc.zip` (no version suffix). Confirmed by inspecting release assets for v1.1.0, v1.2.0, and v1.3.0 — naming has been consistent across all of them.
• Dropped the now-dead `clear_v` helper and its test since nothing else used it.

Test plan

• `cargo build --release` — clean, no warnings on `update.rs`
• `cargo test --release update::` — `asset_name_uses_target_triple` passes
• Cut v1.3.1 and confirm `agentflare update` succeeds on Windows/macOS/Linux

Summary by CodeRabbit

• Bug Fixes
  • Updated release asset and checksum lookup to use platform-specific filenames consistently.
  • Improved download handling for assets named with the agentflare-<platform> format.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Pro Plus

Run ID: 7b038e72-2684-4643-ada0-ca7b60fed9c4

📥 Commits

Reviewing files that changed from the base of the PR and between 8454614 and 2c4f515.

📒 Files selected for processing (1)

• src/update.rs

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📝 Walkthrough

Walkthrough

The updater now builds release and checksum asset filenames from the target platform triple and extension, removing version-based naming and its associated helper.

Changes

Release asset naming

Layer / File(s)	Summary
Update asset filename construction src/update.rs	asset_name now generates agentflare-<target-triple>.<extension> names without incorporating or stripping the release version; related tests reflect the new format.

Estimated code review effort: 2 (Simple) | ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly states the main change: removing version suffixes from platform asset filenames.
Description check	✅ Passed	The description covers the summary and test plan well; the Notes for reviewers section is omitted but non-critical.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/update-asset-name-version-suffix

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