Add Chat top entry PRD and prototype

[AbigailDeng]

Problem

Chat should become the first top-level entry in Aevatar Console and act as the natural-language creation surface for Teams, Members, and Workflows. The MVP needs a shared PRD and prototype before implementation so product/design/backend assumptions are visible.

Solution

• Add a Chat Top Entry MVP PRD covering navigation order, plan-first default behavior, direct-create override, confirmation by button and natural language, from-scratch Team creation, and adding Members to existing Teams.
• Document backend contract notes from the integrate branch, including Team, Member, and workflow provisioning result fields.
• Add a static low-fidelity HTML prototype showing the proposed IA, empty state, plan card, direct-create progress, accepted async states, result cards, and right-side context rail.

Impact Paths

• apps/aevatar-console-web/docs/prd/2026-07-01-chat-top-entry-mvp-prd.md
• apps/aevatar-console-web/docs/prototypes/2026-07-01-chat-top-entry-prototype.html

No runtime application code is changed in this PR.

Validation

• rg -n "5000|5050|Inter|Arial|Roboto|purple|gradient|TODO|FIXME|FIX ME|lorem|Lorem" apps/aevatar-console-web/docs/prd/2026-07-01-chat-top-entry-mvp-prd.md apps/aevatar-console-web/docs/prototypes/2026-07-01-chat-top-entry-prototype.html returned no matches.
• Parsed the prototype HTML with Python html.parser: html_parse_ok.
• Confirmed branch is based on origin/dev.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.83%. Comparing base (cb78de6) to head (f6b8619).
⚠️ Report is 2 commits behind head on dev.

@@           Coverage Diff           @@
##              dev    #2569   +/-   ##
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  Coverage   83.82%   83.83%           
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  Files        1243     1243           
  Lines       95334    95334           
  Branches    12501    12501           
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+ Hits        79917    79919    +2     
+ Misses       9863     9862    -1     
+ Partials     5554     5553    -1     

Flag	Coverage Δ
ci	83.83% <ø> (+<0.01%)	⬆️

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see 1 file with indirect coverage changes

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