Support "=" and "-" separators between an age keyword and its value

[jzonthemtn]

The age filter detects Age: 47 but not Age = 47 or Age - 47. The pattern in phileas/filters/age_filter.py allows only an optional colon:

re.compile(r"\b(age)(d)?(\s*:?\s*)[0-9.]+\b", re.IGNORECASE)

Java broadened this in philterd/phileas#332. Its separator is \s*(?:[:=-]\s*)?, which also accepts = and -, and keeps the whitespace inside the optional group so a run of whitespace can only be matched one way. The current \s*:?\s* has that same ambiguity: two adjacent \s* can split a whitespace run n+1 ways, so a non-matching input backtracks quadratically. SonarCloud flagged the equivalent Java expression as java:S8786.

Acceptance Criteria

• Age = 47 and Age - 47 are detected, alongside the existing Age: 47
• The separator may be omitted or surrounded by whitespace (Age:47, Age : 47, Age 47)
• The whitespace may include a line break, so a label on one line with its value on the next is detected
• Words ending in "age" are not matched (coverage: 47, mileage: 45000)
• Dates such as 2026-01-15 are still not detected as ages
• The separator group is rewritten so a whitespace run has only one possible match, removing the quadratic backtracking in the current \s*:?\s*
• Tests cover the separator forms in tests/test_age_detection.py