docs: add Cohort 7 and Cohort 8 placeholder to Foundation Delegation Program (#2461)

* Initial plan

* docs: add Cohort 7 to FDP cohort information section

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* docs: add Cohort 8 placeholder to FDP page

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Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jcstein <46639943+jcstein@users.noreply.github.com>

Author: Copilot

app/operate/consensus-validators/foundation-delegation-program/page.mdx

@@ -39,6 +39,7 @@ Every 4 months, the Celestia Foundation will distribute a portion of the Foundat
 | Cohort 5 | 15          | 12 months           | Cohort 8          |
 | Cohort 6 | 15          | 12 months           | Cohort 9          |
 | Cohort 7 | 20          | 12 months           | Cohort 10         |
+| Cohort 8 | TBD         | 12 months           | Cohort 11         |
 
 This structure allows for a steady flow of both existing applicants and new applicants to maintain a stable set of participants in the program.
 
@@ -126,3 +127,5 @@ The Foundation will report each cohort’s composition and the duration of their
 - [Cohort 4](https://docs.google.com/spreadsheets/d/1Fxu9uYJ4wxfHChEiSg5bmXAMU8IZSq7J3GYDCFgk1HA/edit?gid=1814073511#gid=1814073511): 20 Validator Seats (Applications open February 1, 2025)
 - [Cohort 5](https://docs.google.com/spreadsheets/d/1Fxu9uYJ4wxfHChEiSg5bmXAMU8IZSq7J3GYDCFgk1HA/edit?gid=1471991269#gid=1471991269): 15 Validator Seats (Applications open June 1, 2025)
 - [Cohort 6](https://docs.google.com/spreadsheets/d/1Fxu9uYJ4wxfHChEiSg5bmXAMU8IZSq7J3GYDCFgk1HA/edit?gid=1010270944): 15 Validator Seats (Applications open October 1, 2025)
+- [Cohort 7](https://forum.celestia.org/t/foundation-delegation-cohort-7-is-live/2232): 20 Validator Seats (Applications open February 1, 2026)
+- Cohort 8: Applications open June 1, 2026 (validators selected in Cohort 5 must reapply)