Quote and encode IMAP mailbox names

[mpscholten]

Draft follow-up for IMAP mailbox handling. This is based directly on current upstream master and intentionally kept separate from #101.

Changes:

• quote and escape mailbox names in public mailbox commands (SELECT, EXAMINE, CREATE, DELETE, RENAME, SUBSCRIBE, UNSUBSCRIBE, STATUS, APPEND, COPY, MOVE)
• encode mailbox command arguments with IMAP modified UTF-7
• decode modified UTF-7 mailbox names returned by LIST/LSUB
• add focused parser/API tests and enable the imap-parsers test suite
• update Source-Repository from git:// to https:// so current cabal check passes

Regression coverage:

• command bytes for quoted mailbox names with spaces and quotes
• command bytes for Entwürfe -> Entw&APw-rfe
• command bytes for A&B -> A&-B
• LIST decoding for Entw&APw-rfe and A&-B

Before wiring the fix, cabal test imap-parsers --test-show-details=direct failed on the new command-byte and LIST decoding tests.

Validation:

• nix shell nixpkgs#cabal-install nixpkgs#ghc --command cabal test imap-parsers --test-show-details=direct
• nix shell nixpkgs#cabal-install nixpkgs#ghc --command cabal build all
• nix shell nixpkgs#cabal-install nixpkgs#ghc --command cabal check (only the existing CHANGELOG doc-place warning remains)
• git diff --check

Note: this draft includes the same imap-parsers test-target setup and https:// repository metadata fix as #101 because it is independently based on upstream master. Once #101 merges, this branch can be rebased to drop that overlap.

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Parse quoted STATUS mailbox names

When mbox contains a space, this now sends a valid quoted STATUS command, but conforming servers echo that mailbox as a string, e.g. * STATUS "foo bar" (...); pStatusLine still discards the name with anyChar manyTill space, so it stops inside the quoted name and then fails to parse the stats. In that scenario status conn "foo bar" ... throws a parse error instead of returning the status; the parser needs to consume an IMAP astring/quoted mailbox before the status list.

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