test: cover saving notification settings, the Telegram poller and Send test

[FMSMITH91]

The rest of notifications.py's zero-coverage functions.

The one that matters

save_settings treats a None secret as "keep what's stored", because the settings form never round-trips a real token back to the server. If that ever broke, every unrelated checkbox change would silently wipe the bot token — and alerts would just stop, with no error and nothing on screen.

Asserted both directions: None keeps the stored value, a real value replaces it and is written encrypted (plaintext must not appear in the config, and it must decrypt back).

Also covered

• Thresholds clamp to their bounds rather than storing whatever was posted, and junk in a numeric field is ignored instead of overwriting a good value
• The Telegram poller returns None for a malformed or empty token without building a URL
• Send test explains what's missing — five cases, each naming the field — rather than failing mute

On safety

update_config is stubbed throughout, so the real data/config.json is never written by these. Verified: the file's bytes are unchanged across a run.

Its mtime does move, but that predates this change — I checked, and the suite already rewrote it byte-identically at HEAD. Not introduced here, and harmless, but worth knowing.

Mutation-verified:

None token overwrites instead of keeping -> 1 fail
secrets stored in the clear              -> 1 fail
thresholds no longer clamped             -> 1 fail

unit 854 → 867 · lint clean.

🤖 Generated with Claude Code

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Coverage ∅ diff coverage · +0.38% coverage variation

Metric	Results
Coverage variation	✅ +0.38% coverage variation (-1.00%)
Diff coverage	✅ ∅ diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (0b52813)	11965	5823	48.67%
Head commit (d73721b)	11965 (+0)	5869 (+46)	49.05% (+0.38%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#72)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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