Add guided sport and competitor config flow

[Chreece]

Dependency

Depends on #364.

This PR is stacked directly on the current narrow #364 soccer/all fix
(9610957b33d18dd22e865925e6c3ab9e92f06112).

PR #364 does not introduce a new all-sports universal runtime. It remains
limited to the reproduced ESPN soccer/all gaps.

Summary

Add a guided sport → competitor → competition setup flow while keeping
Advanced / Custom API available.

The guided flow:

1. chooses a sport;
2. searches for a team or athlete;
3. lets the user select the canonical ESPN competitor;
4. offers verified competition choices plus All competitions;
5. creates the Team Tracker entry.

Scope

This PR contains only guided setup/UI work:

• custom_components/teamtracker/config_flow.py
• custom_components/teamtracker/strings.json
• translation catalogs
• tests/test_config_flow.py
• tests/test_config_flow_soccer_all_discovery.py
• tests/test_guided_translations.py

It does not add or change runtime providers/parsers. TheSportsDB remains
separate in PR #369.

All competitions

The All competitions choice maps to Team Tracker's existing
league_path: all behavior.

This PR does not claim to expand ESPN/Team Tracker all runtime support to
every sport. Coverage remains dependent on the existing provider behavior and
what ESPN exposes for the selected sport.

For soccer, the missing aggregate-feed/setup cases are handled by the narrow
changes in PR #364.

Search behavior

Teams

• discover current ESPN league paths for the chosen sport;
• search league team collections;
• deduplicate only by canonical numeric ESPN team ID;
• preserve distinct IDs even when names are similar;
• use conservative local fuzzy/transliteration matching.

Individual sports

Guided search supports Golf, MMA, Racing and Tennis.

• ESPN search is used as a canonical identity source;
• results are independently sport-checked;
• numeric athlete IDs are extracted from ESPN identity data;
• collection presence is not treated as proof of competition membership.

Competition choices

Specific competition choices are derived from real ESPN schedule/event
evidence for the selected competitor.

The All competitions option uses the existing runtime path described above;
it is not backed by a new universal provider in #364.

Translations

The guided UI includes the existing translation set shipped on this branch,
including Greek Όλες οι διοργανώσεις.

Status

This PR remains Draft while #364 is reviewed.

The branch has been rebuilt so its direct parent is the restored narrow #364
head and its own delta contains only config-flow, translations, and their
tests.

[Chreece]

Rebased this guided setup flow on the reduced #364 implementation.

The flow still provides sport → competitor search → competition / All competitions, but no longer depends on the discarded universal ESPN runtime. Soccer discovery now reuses #364's live league discovery, numeric ESPN IDs stay internal, and athlete entries keep the human-name runtime format already supported upstream.

No parser, coordinator, sensor, provider-factory, or event-state changes are included. The updated config-flow regressions and full suite pass.

Of course it needs broader user testing...