Convert dict() calls to literals and improve typing with TypedDicts

[Copilot]

Continues typing work from PR #223 (dmarc.py) by converting all dict() constructor calls to literal dictionaries and fixing TypedDict definitions across remaining modules to enable proper type checking.

Changes

Dictionary constructor conversions (~60 instances)

• dict() → {}
• dict(key=value) → {"key": value}
• dict([("key", value)]) → {"key": value}
• Nested constant structures (BIMI_TAGS, mta_sts_tags, smtp_rpt_tags)

TypedDict fixes and cast removal

• Fixed SMTPTLSReportingTags: was single value TypedDict, now dict[str, SMTPTLSReportingTagValue]
• Fixed MTASTSTags: was single value TypedDict, now dict[str, str]
• Fixed ParsedMTASTSPolicy: field name "v" → "version" to match implementation
• Removed 5 cast() calls by properly typing dictionary construction

Type refinement

• check_mta_sts: dict[str, Any] → MTASTSCheckResults (Union of success/failure TypedDicts)
• Proper initialization of TypedDict-typed variables instead of dynamic dict building

# Before
mta_sts_results = dict([("valid", True)])
mta_sts_results["id"] = ...
mta_sts_results["policy"] = ...

# After
mta_sts_results: MTASTSCheckSuccess = {
    "valid": True,
    "id": id_value,
    "policy": policy["policy"],
    "warnings": warnings,
}

Python 3.9 compatibility

• Union[] syntax (no pipe unions)
• dict[str, ...] type aliases per PEP 585 (matches dmarc.py pattern)
• No NotRequired usage

Original prompt

Continue the work of this PR that added explcit dmarc.py typing to all of the other moduls in checkdmarc. First, convert any use of dict() or OrderedDict() to a literal dictionary so that typing can work correctly. You must avoid any uses of casting or any, and prefer typedicts instead. The code must be compatible with python 3.9 and up. Keep code changes as simple and minimal as posible to complete the typing task without causing drift and possibly introducing new bugs. The code must pass pylance and ruff checks. Doo not use syntax that cannot be used in Python 3.9, such as NotRequired or pipe unions.

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[seanthegeek]

@copilot Run tests.py and make sure al tests pass

[Copilot]

@copilot Run tests.py and make sure al tests pass

All tests pass ✓ (29 tests run, 2 skipped, 0 failures)

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