fix(logs): match log filters case-insensitively, message as a substring

[mobile-kevin]

Problem

device logs filter matching was exact and case-sensitive, so the obvious filters silently matched nothing:

• --filter level=error never matched "Error" (and iOS/Android capitalize levels differently, so there was no portable spelling).
• --filter message=<text> required the field to equal the whole log line, so a substring never matched.

With --limit set, a filter that matches nothing streams forever waiting for entries that never arrive, which reads as a hang.

Fix

• Compare every field case-insensitively (strings.EqualFold).
• Match message as a case-insensitive substring.
• Help text documents both.

Tests

• Unit: level=error/ERROR match Error, case-insensitive exclude, case-insensitive process, and message substring matching (case-insensitive, include + exclude).
• Verified live: level=error and message=<substring> now return matching entries promptly instead of hanging.

[coderabbitai]

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📥 Commits

Reviewing files that changed from the base of the PR and between 1e88c68 and fd4383c.

📒 Files selected for processing (3)

• cli/logs.go
• commands/logs.go
• commands/logs_test.go

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