fix: encode file paths for DIAL Core requests

[andrii-novikov]

Applicable issues

• fixes Quick app 2.0 with switched on Files tools can not perform actions with pdf Context files from Organization or Shared with me #447

Description of changes

Copying a context file whose name contains spaces or parens (e.g. Uno-Rules-PDF-Official-Rules-unorules.org_ (1).pdf) fails with a DIAL Core 500 (java.net.URISyntaxException: Illegal character in path). File URLs flow to Core verbatim: aidial_client performs no path encoding, and copy_to/move_to put the URLs in an ops/resource/* JSON body that the HTTP client never touches, so nothing on the wire ever encodes them.

Key changes:

• DialFileService now owns a URL contract: decoded (human-readable) files/... URLs in and out; percent-encoding is an internal egress concern. A private _encode helper (quote(unquote(url), safe="/")) is applied immediately before every aidial_client call — metadata lookup, download, upload, delete, and both source and destination of copy/move (the exact path Quick app 2.0 with switched on Files tools can not perform actions with pdf Context files from Organization or Shared with me #447 dies on). Unquote-then-quote makes it idempotent, so already-encoded and decoded inputs both land on the same encoded spelling; safe="/" preserves the trailing / that folder metadata lookups rely on. Accepted edge case (documented at the helper): a filename literally containing a valid %XX sequence is indistinguishable from its encoded form and gets normalized.
• Ingress is decoded: list_folder builds FolderEntry.url from unquote(item.url) (Core returns encoded URLs), so the file tools (list/find/search glob matching, display paths) operate on decoded names with zero encoding awareness in the tooling layer.
• StateHolder file-cache keys get the same normalization, so the encoded and decoded spellings of one file share a single cache entry across every cache user (DialFileService and FileLoaderService/DialDownloader populate the same per-request cache); invalidation on write/delete/move can no longer miss an entry stored under the other spelling.

Tests: egress encoding for spaces/parens, idempotence (no double-encoding), trailing-slash preservation, copy/move encoding both URLs, decoded list_folder output, cache hits and invalidation across spellings, decoded multipart filename on upload, and a find tool test proving a human-readable glob matches a space-bearing filename. make lint and the full unit suite (1628 tests) pass.

Checklist

• Title of the pull request follows Conventional Commits specification
• [ ] Design documented is updated/created and approved by the team (if applicable) (bug fix, no design doc)
• [ ] Documentation is updated/created (if applicable) (no user-facing config or behavior contract change)
• Changes are tested on review environment
• [ ] App schema changes are backward compatible, or breaking changes are documented with a migration guide (no config model changes; schema check green)
• Integration tests pass

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[ypldan]

Shouldn't that logic belong to aidial-client library?